Chair with means for controlling a cursor

ABSTRACT

The invention relates to a chair comprising at least a chassis; and a seat, as well as means suitable for converting chair movements into control signals for controlling a cursor (pointer) on a display screen. In order to prevent RSI complaints, the invention aims at providing an improved chair, which is characterized in that the seat comprises a convex part, which part can be movably accommodated in a corresponding part of the chassis having a complementary concave shape, and in that the means for controlling the cursor are at least in part disposed at the location of the mating area between said convex and concave parts.

The invention relates to a chair comprising at least a chassis; and aseat, as well as means suitable for converting chair movements intocontrol signals for controlling a cursor (pointer) on a display screen.

Such a chair is known from U.S. Pat. No. 5,909,208 in the name of MrBlomdahl, it provides means which converts rotary movement and tiltingmovement of the chair into control signals, which may be used forcontrolling a cursor (mouse pointer) on a display screen of, forexample, a computer. Said control means are intended to prevent injuriescaused by intensive computer use, which injuries are known by thegeneral designation “mouse problem” or RSI (Repetitive Strain Injury).

RSI or Repetitive Strain Injury is a collective term used for a numberof physical complaints in the muscles, tendons and nerves of inparticular the arms and the upper part of the body of computer workers.Although in particular the national authorities have recognised theproblem of RSI for a number of years and have been taking direct actionin the form of giving advice and taking RSI-reducing measures, forexample by providing ergonomic aids, the occurrence of RSI and therelated physical complaints form an ever increasing problem. Theaforesaid patent aims at providing an ergonomic solution so as to reduceor prevent the occurrence of RSI among computer workers and even toprovide a cure in those cases where it should occur.

RSI complaints can roughly be traced back to an ergonomically wrongseating position of the person in the chair in front of the displayscreen of a computer. A hunched position of the upper part of the bodynot only leads to an obstruction of the airways and thus to a lessoptimum uptake of oxygen in the blood, but it also causes the nerves andthe blood vessels to the arms (thoracic outlet) to be pinched. These twocauses are primary factors that contribute towards an insufficientsupply of blood and oxygen to the arms and in particular to the hands bymeans of which a generally known mouse pointer is controlled.

Furthermore, a constantly repeated movement of the index finger on oneof the control buttons of the mouse pointer leads to an increasedfriction of the tendons in the tendon sheaths of the hand. Also thepressure of the wrist resting on the supporting surface leads to anincreased compression of the tendons and the tendon sheaths, thusincreasing the risk of tissue injury. When the mouse pointer iscontrolled in this starting position, dorsal flexion and ulnar abductionof the wrist take place, which is an ergonomically unfavourable positionand which leads to an abnormal strain on the tendons and the tendonsheaths in the wrist joint.

Another drawback in particular of the aforesaid U.S. Pat. No. 5,909,208is connected with the chair that is used in said patent, which chairleads to an undesirable and unnecessary strain on the vertebral columnand the upper extremities (the neck and the arms) due to the fact thatthe person remains in the same seating position too long. All in all,the above causes lead to an inadequate transport of blood and oxygen tothe arms, as a result of which an ergonomically unacceptable strain isplaced in particular on the muscles and the nerves thereof.

The object of the present invention is precisely to provide a chairwhich is to prevent all kinds of physical complaints that can be reducedto RSI, which chair does not have the drawbacks of the chair that isknown from U.S. Pat. No. 5,909,208.

In order to accomplish that objective, the chair is according to theinvention characterized in that the seat comprises a convex part, whichpart can be movably accommodated in a corresponding part of the chassishaving a complementary concave shape, and in that the means forcontrolling the cursor are at least in part disposed at the location ofthe mating area between said convex and concave parts.

Said construction not only relieves some of the strain on the arm usedfor operating the mouse, but in addition this construction of the seatand the chassis has a positive influence on the seating position of theperson seated on the chair in question, as a result of which inparticular the oxygen uptake by the lungs and consequently the supply ofblood rich in oxygen to the arms and the upper part of the body isstrongly stimulated. On the other hand, the person in question no longerneeds to operate the mouse with his arms, so that all kinds of RSIcomplaints as described above are prevented.

It should be noted that the terms “convex” and “concave” relate tocurved surfaces having one radius as well as to surfaces having a radiuswhich varies along the surface. Consequently, the invention is notlimited to convex and concave surfaces having one radius, but it mayalso extend to curved surfaces having an ellipsoidal shape, a parabolicshape or another curved shape.

More in particular, according to one embodiment the seat is movable inat least two orthogonal directions relative to the chassis.

In one embodiment, the seat may comprise an upright ring formed on theconvex part of the seat, which ring limits the movement of the seatrelative to the chassis to a particular angular range. This furthermoreprevents fingers, clothes etc. getting wedged.

It has become apparent that in order to achieve an effective control ofthe moue pointer on the display screen, the seat must be movable throughan angle of 10°-20° relative to the chassis.

A smooth and effective movement of the seat on the chassis can beobtained in that the convex part of the seat can be supported on theconvex part of the chassis via ball bearings in one embodiment.

In order to achieve an effective control of the mouse pointer (cursor)on the display screen, the chair may according to the invention becharacterized in that the ball bearings form part of the control means.

Furthermore, said means may be mounted at least in the seat of thechair, and a specific embodiment of the chair is characterized in thatsaid means comprise at least a balance switch or tumbler switch, forexample a mercury switch.

In another embodiment, the control means control the cursor (pointer) onthe display screen by remote control. The remote control means may beoptical control means or electromagnetic control means.

On the other hand, the chair according to the invention, which isfurthermore fitted with two armrests, may be characterized in that saidarmrests are provided with means for (un)locking the movable seatrelative to the chassis. The hinged joints may be made up of snaphinges. Thus the user can utilise his chair in a quick and effectivemanner for controlling the cursor on the display screen and, if thecomputer is not used for a particular period of time, locking themovable seat in position relative to the chassis, so that the chair arecan also be used as an ordinary chair in this position.

It has become apparent that in order to achieve an ergonomic seatingposition, which is desirable with a view to preventing RSI complaints,the convex part of the seat preferably forms part of a fictitioussphere, whose centre is located between the shoulder blades of a personseated on the chair.

It has been established by experiment that the radius R of thefictitious sphere ranges from 40-120 cm, preferably it is 75 cm.

The invention will be explained in more detail hereinafter withreference to a drawing, in which:

FIGS. 1A-1C show a first embodiment of an ergonomic chair according tothe invention (rear side view);

FIGS. 2A-2C show the embodiment of the ergonomic chair of FIGS. 1A-1C(side view);

FIG. 3 shows another embodiment of an ergonomic chair according to theinvention; and

FIG. 4 shows yet another embodiment of an ergonomic chair according tothe invention.

In FIGS. 1A-1C and 2A-2C an embodiment of an ergonomic chair accordingto the invention is shown in rear views and in side view, respectively.

The chair is schematically represented and indicated by numeral 1. Thechair comprises at least at chassis 2 and a seat 3, on which a person 4(schematically shown) is seated. In FIGS. 1A-1C and 2A-2C, only thevertebral column 4 a and the head of the person are schematically shown.The chair comprises means (schematically represented by the rectangleindicated at 7), which means are connected to a suitable connector (notshown) of a computer 5 via suitable signal lines. Since the means 7function to convert movements of the chair into control signals 8 forcontrolling the cursor (mouse pointer) 6 on the display screen 5, theconnector of the computer 5, to which the control means 7 are connected,may be a well-known COM port or PS/1 connector, for example, which isspecifically intended for connecting a mouse pointer device.

According to the invention the seat 3 comprises a convex part 3 a, whichcan be movably accommodated in a corresponding part 2 a of the chassis 2having a complementary concave shape. More in particular, said convexand said concave part of the seat 3 and said chassis 2, respectively,are geared to each other in such a manner that the seat 3 can move in atleast two orthogonal directions relative to the chassis 2. The anglethrough which the seat can move relative to the chassis preferablyranges from 10°-20° (established by experiment).

The radius of movement of the seat is limited to this range bymechanical means, for example—as shown in FIG. 3—by means of an uprightring 3 b. Said ring 3 b is formed on the convex part 3 a of the seat 3and extends circumferentially. The ring 3 b forms a stop for limitingthe maximum movement of the seat 3 relative to the chassis 2. Inaddition to that, the ring 3 b functions as a protective device toprevent the occupant's clothes and fingers from getting wedged betweenthe seat 3 and the chassis 2.

In one embodiment, which is shown in FIGS. 1A-1C and FIGS. 2A-2C, theconvex part 3 a of the seat 3 can be movably accommodated in the convexpart 2 a of the chassis 2 via ball bearings 5. Said ball bearings 5 arepresent at the location of the mating area between the convex part ofthe seat 3 and the concave part of the chassis 2. As FIGS. 1A-1C andFIGS. 2A-2C show, the ball bearings, at least one of said ball bearings,forms part of the control means 7. To this end the ball bearing 5 isprovided with suitable detecting means or sensors, which convert therotary movement of the ball bearing 5 into suitable control signals viaa connection 7 a, which control signals are subsequently used by thecontrol means 7 for controlling the mouse cursor (pointer) 6 on thedisplay screen 5 a via the connection 8.

In another embodiment, which is shown in FIGS. 1A-1C and FIGS. 2A-2C,the control means 7 furthermore comprises one or more switches 9 a-9 bmounted in the seat 3 of the chair 1.

Movements to the left and to the right can be detected by means of thebalance switch 9 a and be converted by the control means 7 into suitablecontrol signals for moving the cursor 6 to the left and to the right,respectively, on the display screen. Likewise, movements to the rear andto the front of the seat 3 can be detected by means of the balanceswitch 9 b (FIGS. 2A-2C) and be converted by the control means 7 intosuitable control signals 8 for moving the mouse cursor down and up,respectively, on the display screen 5 a. To this end, both the balanceswitch 9 a and the balance switch 9 b are connected to the control means7 by means of suitable cables (not shown).

Said movements can also be converted by the ball bearing 5, of course,which bearing is connected to the control means 7 by means of the signalwire 7 a.

In another embodiment, on the other hand, the control means 7 controlthe cursor (pointer) 6 on the display screen 5 a in a contactlessmanner. The contactless control means may be optical control means, inwhich case one or more light-emitting elements, for example LEDs, whichco-operate with light-receiving sensors, are mounted at the location ofthe mating area 2 a-3 a between the concave part 2 a and the convex part3 a. The movement of the light-emitting elements and the light-receivingsensors relative to each other caused by the movement of the seat 3relative to the chassis 2 is converted into a change in the position ofthe cursor 6 on the display screen 5 a.

The control means 7 may also be electromagnetic control means,comprising one or more electromagnetic coils that cooperate withmagnets. Movement of a magnet with respect to an electromagnetic coilwill lead to an electrical signal according to the principle ofelectromagnetic induction, on the basis of which the cursor 6 ispositioned on the display screen 5 a.

The curvature of the convex part 3 a of the seat 3 forms part of afictitious sphere, whose centre is preferably located between theshoulder blades of the person 4 present on the seat 3. The radius R ofsaid fictitious sphere may range from 40-120 cm, preferably it is 70 cm.All this as shown in FIGS. 1A-1C and 2A-2C, respectively.

FIG. 4 shows a supporting surface 11, for example a desktop, from above.Present behind the desktop 11 is the chair 2 according to the invention,which is provided with armrests 10 a and 10 b, which, in accordance withthe invention, can be moved reciprocatingly (see the double arrows inFIG. 4) for (un)locking the seat relative to the chassis.

According to the invention, the mouse pointer is controlled by the chairrather than by the usual mouse. In this embodiment, the well-known mousebuttons are large control buttons 13 a and 30 b placed beside thekeyboard 12, with the button 13 a performing the function of “left-handmouse button” and the button 13 b performing the function of “right-handmouse button”. Depending on the physical possibilities of the user (hemay be left-handed or right-handed or be handicapped on the left or onthe right, and consequently be immobile on that side), the mouse buttonsmay be placed on the left (13 a-13 b) or on the right (13 a′-13 b′). Thelarge control buttons only require a low coordinating capacity of theuser (which is favourable if the user should have a handicap) and do notplace a strain on the wrist joint, the tendons and the tendon sheaths asdescribed above, since the buttons can be controlled with a clenchedfist or hand.

It will be understood that RSI complaints can be prevented with thisdesign of an ergonomic chair, the more so because the head and theshoulders of the person 4 do not move during any of the movements of theseat 3 as a result of the convex shape of the seat 3. This enables theuser not only to view the display screen 5 a more at ease, but inaddition the vertebral column and in particular the shoulders of theuser are not strained unnecessarily, which might lead to RSI complaintsin the shoulders, the arms and/or the hands.

In addition to that, such a chair is very suitable for use byhandicapped persons, since it is usually easier for persons who have ahandicap to move the mouse pointer via the pelvis or the (lower) back.This is certainly the case with persons who have a hand or arm handicap,since higher coordinative skills are required in particular of the hand,which skills are not available due to handicap of the hand or the arm.

In addition to that, such a chair may be very suitable for playingcomputer games and video games, because the perception of the game canbe significantly enhanced during play if the game can be played bychoosing a variable angle of inclination. Think of space travel/flightsimulation games, car racing games, skiing games, surfing games etc.etc. in this connection.

1. A chair comprising at least a chassis; and a seat, and a controllerfor converting chair movements into control signals for controlling acursor on a display screen, wherein the seat comprises a convex partthat can be movably accommodated in a corresponding part of the chassishaving a complementary concave shape, and the controller is at least inpart disposed proximate a mating area between the convex and concaveparts.
 2. A chair according to claim 1, wherein the seat can move in atleast two orthogonal directions relative to the chassis.
 3. A chairaccording to claim 1, wherein the seat comprises an upright ring formedon the convex part of the seat, which ring limits movement of the seatrelative to the chassis to an angular range.
 4. A chair according toclaim 3, wherein the seat can move through an angle of 10°-20° relativeto the chassis.
 5. A chair according to claim 1, comprising ballbearings for supporting the convex part of the seat can be supported onthe convex part of the chassis.
 6. A chair according to claim 5, whereinthe ball bearings form part of the controller.
 7. A chair according toclaim 1, wherein the controller is at least partially mounted in theseat.
 8. A chair according to claim 1, wherein the controller includesat least one of a balance switch or tumbler switch.
 9. A chair accordingto claim 1, wherein the controller controls the cursor on the displayscreen in a contactless manner.
 10. A chair according to claim 9,wherein the controller includes an optical controller for controllingthe cursor.
 11. A chair according to claim 9, wherein the controllerincludes an electromagnetic controller for controlling the cursor.
 12. Achair according to claim 1, comprising at least one armrest providedwith means for locking the seat relative to the chassis.
 13. A chairaccording to claim 12, wherein the locking means includes snap hinges.14. A chair according to claim 1, wherein the convex part of the seatforms part of a fictitious sphere having a center arranged to be locatedbetween the shoulder blades of a person seated on the chair.
 15. A chairaccording to claim 14, wherein a radius R of the fictitious sphereranges from 40-120 cm.
 16. A chair according to claim 2, wherein theseat comprises an upright ring formed on the convex part of the seat,which ring limits movement of the seat relative to the chassis to anangular range.
 17. A chair according to claim 2, wherein the controlleris at least partially mounted in the seat.
 18. A chair according toclaim 17, wherein the controller includes at least one of a balanceswitch or tumbler switch.
 19. A chair according to claim 7, wherein thecontroller includes at least one of a balance switch or tumbler switch.20. A chair according to claim 2, wherein the controller controls thecursor on the display screen in a contactless manner.